Localization versus inhomogeneous superfluidity: Submonolayer He-4 on fluorographene, hexagonal boron nitride, and graphene

We study a sub monolayer He-4 adsorbed on fluorographene (GF) and on hexagonal boron nitride (hBN) at low coverage. The adsorption potentials have been computed ab-initio with a suitable density functional theory including dispersion forces. The properties of the adsorbed He-4 atoms have been computed at finite temperature with path integral Monte Carlo and at T=0 K with variational path integral. From both methods we find that the lowest energy state of He-4 on GF is a superfluid. Due to the very large corrugation of the adsorption potential this superfluid has a very strong spatial anisotropy, the ratio between the largest and smallest areal density being about 6, the superfluid fraction at the lowest T is about 55%, and the temperature of the transition to the normal state is in the range 0.5-1 K. Thus, GF offers a platform for studying the properties of a strongly interacting highly anisotropic bosonic superfluid. At a larger coverage He-4 has a transition to an ordered commensurate state with occupation of 1/6 of the adsorption sites. This phase is stable up to a transition temperature located between 0.5 and 1~K. The system has a triangular order similar to that of He-4 on graphite. The lowest energy state of He-4 on hBN is an ordered commensurate state with occupation of 1/3 of the adsorption sites and triangular symmetry. A disordered state is present at lower coverage as a metastable state. In the presence of an electric field the corrugation of the adsorption potential is slightly increased but up to a magnitude of 1 V/Ang. the effect is small and does not change the stability of the phases of He-4 on GF and hBN. We have verified that also in the case of graphene such electric field does not modify the stability of the commensurate sqrt{3}*sqrt{3}R30 phase.Comment: 12 pages, 14 figure

numerical and experimental validation of a non standard specimen for uniaxial tensile test

Abstract Material testing is a fundamental activity for the characterization of materials mechanical properties and for the certification of product quality. With concepts such as Smart Factories and Industry 4.0 coming to the fore, testing and measurement is moving away from laboratories and closer to the production floor: MaCh 3D is a miniaturized tensile testing machine developed for products and materials certification directly on the production site. The heart of the technology is the specimen with non-conventional geometry for tensile tests developed so as to be easily installed on the machine. The objective of this work is to illustrate the process of determining the geometry of specimen and fixtures by numerical analysis and their experimental validation, comparing the results with those obtained from specimens according to ASTM D638 standard, ASTM International, (1999)

Near-Reference Air Quality Sensors Can Support Local Planning: A Performance Assessment in Milan, Italy

At present, 4.2 million deaths occur every year due to ambient air pollution, according to the World Health Organization. In view of reducing such a figure, air quality monitoring and reliable data are essential. Nevertheless, local authorities in urban environments, where pollution levels are highest, often face a dilemma. On the one hand, the high costs of reference monitors make their largescale adoption prohibitive, while the easily scalable low-cost sensors often feature significantly lower data quality and lack of calibration. Near reference monitors have been voiced as a promising solution, as they exhibit limited costs, though specific studies assessing their performance against reference monitors are still lacking. This article provides an in-depth assessment of three near reference sensors’ stations performance, through their collocation with regional reference monitors from December 2021 onwards. Two sensors were positioned at high-traffic locations, while the third recorded background pollution levels in Milan, Italy. The sensors’ performance was quantified not only via the coefficient of determination (R2) and the regression model, but also with the Mean Normalized Bias (MNB) and median values. After a first measurement period, sensors were re-calibrated to also appraise their behavioral change, generally exhibiting a performance increase. Results show high correlation for all hourly-recorded pollutants, with peaks for Ozone (O3) (R2 = 0.94) and BC (R2 = 0.93). Although location-specific, such results show an interesting potential for near reference sensors in support of urban air quality planning

Hastening Time to Ejaculation in Donkey Jacks Treated with the PGF2α Analog, Cloprostenol Sodium

Due to the long courtship needed to attain excitation and erection, donkey semen collection can take up to 90 min. ProstaglandinF2α (PGF2α) has been reported to hasten the onset of erection and ejaculation in domesticated mammals, presumably by inducing smooth muscle contractions in the internal genitalia. However, while it has been anecdotally used in donkeys, it has yet to be critically evaluated. This study aimed to compare behavioral and semen parameters in Catalan, Balearic, Amiata, and Miranda jacks treated with the PGF2α analogue cloprostenol sodium immediately prior to exposure to an estrus jenny. Nineteen donkeys were assigned in a crossover design to receive cloprostenol sodium (125µg, i.m.; n = 53 collections) or saline (1 mL, i.m.; n = 53 collections). There were no differences for erection (52/53 vs. 52/53) or ejaculation (52/53 vs. 48/53) for collection attempts assigned to saline or cloprostenol sodium, respectively. Cloprostenol sodium significantly hastened treatment-to-erection and treatment-to-ejaculation times from 12.0 ± 1.6 to 6.0 ± 1.6 min and from 14.0 ± 1.4 to 9.6 ± 1.4 min, respectively. Significant effects of breed and age were observed in behavioral and parameters, but there were no effects of cloprostenol sodium administration on semen parameters. In conclusion, cloprostenol sodium administration immediately prior to semen collection hastened time to collect semen in donkeys with no detrimental effects on semen quality and can be used by practitioners to circumvent long delays in donkey semen collection

Iron Speciation of Natural and Anthropogenic Dust by Spectroscopic and Chemical Methods

In this work, we have characterized the iron local structure in samples of two different types of atmospheric dust using X-ray absorption spectroscopy and selective leaching experiments. Specifically, we have investigated samples of long-range transported Saharan dust and freshly emitted steel plant fumes with the aim of individuating possible fingerprints of iron in the two cases. Findings include (1) prevalence of octahedral coordinated Fe 3 + for all samples; (2) presence of 6-fold coordinated Fe 3 + , aluminosilicates and iron oxy(hydr)oxides in Saharan dust and (3) of Fe-bearing spinel-like structures in the industrial fumes; (4) general predominance of the residual insoluble fraction with a notable difference: 69% for Saharan dust and 93% for steel production emissions, associated with aluminosilicates and non-reducible iron oxy(hydr)oxides, and Fe spinels, respectively. The remarkable differences between the X-ray absorption spectroscopy (XAS) spectra and leaching test results for the two sample types suggest the possibility to exploit the present approach in more complex cases. To this aim, two additional case studies of mixed aerosol samples are presented and discussed

A multi-society position paper on the prevention and management of nosocomial and severe infections: the Italian Society for Infectious Diseases, the Italian Multidisciplinary Society of Hospital Infections, the Italian Society of Chemotherapy, the Italian Society of Respiratory Medicine, the Italian Society of Clinical Microbiology, the Italian Society of Microbiology, and GISIG (Italian Study Group on Severe Infections)

Amulti-society position paper on the prevention and management of nosocomial and severe infections: the Italian Society for Infectious Diseases, the Italian Multidisciplinary Society of Hospital Infections, the Italian Society of Chemotherapy, the Italian Society of Respiratory Medicine, the Italian Society of Clinical Microbiology, the Italian Society of Microbiology, and GISIG (Italian Study Group on Severe Infections

fracture toughness of structural adhesives for the automotive industry

Abstract Adhesive bonding is currently employed by automotive manufacturers to complement (or replace) welding in joining dissimilar materials. In order to reduce the impact on the existing manufacturing infrastructures, structural adhesives are deployed in the body shop but hardening is accomplished in the paint cure oven. Various adhesive formulations have been specifically developed for the implementation in the automotive manufacturing chain. However, it is very important to assess the mechanical behaviour of the joints which results from the peculiar curing strategy. In the present work, automotive grade single component epoxy and two component epoxy modified acrylic adhesives were evaluated. T-joints were fabricated using a cold rolled galvanized steel (FeP04) employed in the production of car body parts. The fracture toughness of the joints was determined using the test protocol proposed by the European Structural Integrity Society (ESIS). Optical microscopy was employed to ascertain the mechanisms of failure. The results indicated that both adhesives were able to provide a fairly good mechanical response with minimum preparation of the mating substrates. Moreover, the obtained values of fracture toughness were shown to be essentially independent of the adhesive layer thickness

Uniaxial magnetic anisotropy tuned by nanoscale ripple formation: ion-sculpting of Co/Cu(001) thin films

We have investigated the growth of surface nanostructures on a Co/Cu(001) film and the growth of Co films on a nanostructured Cu(001) substrate as well as the effect of nanoscale pattern formation on the film magnetic properties. Here we demonstrate by scanning tunneling microscopy measurements and magneto-optic Kerr effect hysteresis curves that low-temperature grazing-incidence ion sputtering can be used to induce the formation of nanoscale ripples which reduce the four-fold symmetry of the Co film to two-fold, thus generating a strong in-plane uniaxial magnetic anisotropy. The nanostructures and the associated uniaxial magnetic anisotropy were found to be stable up to room temperature

Correction to: Rubiola et al. Risk Factors for Bovine Cysticercosis in North-West Italy: A Multi-Year Case-Control Study. (Animals 2021, 11, 3049)

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